JRuby 1.3RC1 is now available. The changes (from the release notes):
- Fixes so that JRuby runs in restricted environments better like GAE/J
- Accessing primitive Java arrays are about 10x faster
- timeout.rb is now ~40% faster
- irb works in --1.9 mode now
- Additional Miscellaneous 1.9 fixes
- rubygems 1.3.2 and rspec 1.2.6 upgrades
One of the changes mentioned was the 40 % faster timeout functionality; the changes to timeout, a rewrite from Ruby to Java, can be seen in the GitHub commit.
Another change is the removal of Java 1.4 support.
Finally, work continues on reducing the startup overhead of JRuby and Java. Charles Nutter writes about integrating Nailgun into JRuby:
Ideally, jruby --ng would be the only flag, and it will start up a server (or n servers) as needed to handle commands. If that's desirable, we need work to make it happen.
Basically, Nailgun starts one or more JRuby instances. Clients can tell the servers to run programs - since the JRuby instance is already running, there's no startup overhead to pay. Currently more work needs to be done to configure Nailgun and set it up with the right amount of servers.